Within the general class of reciprocating piston devices, there are countless mechanisms which accomplish the task of converting the pressure of expanding gas into rotary motion or, conversely, using a rotary input to pump a fluid. Statistically, pistons are most, commonly coupled to a rotating crank, via a connecting rod, but several engines have been known which use cams to couple the reciprocating motion of pistons to the rotary motion of a shaft. Similarly, while most such devices use a stationary cylinder and reciprocating pistons, there are several known designs, generally called rotary engines, in which the cylinders, or the pistons, or both, revolve. Likewise, the valves controlling the gas flow may be poppet valves, slide valves, rotary valves, sleeve valves, or simply ports which are covered and uncovered by the piston motion, as in the common two-stroke gasoline engine.
Sleeve valves themselves are well known, and have a number of recognized advantages, as compared to other types of valves in engines and pumps. A sleeve valve is simple, being formed by placing a port or ports in the wall of a moving sleeve which surrounds the reciprocating piston(s) and forms a cylinder. The sleeve usually is reciprocated in a circumferential direction, and its ports cooperate with related ports in the housing, thus requiring minimum additional parts, and the sleeve valve is not subject to inertial effects, such as the "valve float" experienced at high speed with reciprocably operating spring-loaded poppet valves and their associated actuating mechanisms.
However, it appears there has never been any recognition of the unique advantages which might be achieved by combining a sleeve valve controlled device using reciprocating piston(s) with a cam mechanism cooperating with the piston(s) to achieve timing and power extraction from the device.